All about stoves – History – Use – Repair – Ask BernieDawg

Main menu

Post navigation

Silent Cap for 111B?

Hello BernieDawg, I’m sure you’ve received this question before, but I’ll go ahead and ask. Do you have a silent damper for the Optimus 111 stove (hiker) with the “roarer” burner?Thanks,“Bugged by Noise”

Hi, “Bugged”
Thanks for your question and your interest in my silent cap products. I *have* received this question quite a few times.

The short answer to your question is no. No one anywhere to date has a silencing product to work on your 111 roarer burner. Sorry.

Now, in the past, some folks have gotten all mad and upset about this. It’s almost like they think I’m holding out on them or something. So, I hope you won’t mind too much if I try to show why I do not have any caps for the 111 style burner.

Here’s the explanation. The standard 111 or 111B burners have the traditional shaped design where the vaporization chamber is above the jet. Fuel moves into that chunk of metal above the jet (the burner “head” or vaporization chamber), the fuel is heated into a vapor up top and then the vapor moves down a tube, into the jet and spews upward as flame to heat the vapo chamber. It’s pretty neat how these work, really. These burners look like this one on a Optimus 22:

All silent caps, mine or others, are designed to work with another, and very different, type of roarer burner where the design uses a bell-shaped structure. Here’s a Dragonfly burner without it’s flame plate in place. With this burner, the jet spews vapor upward which hits a flame plate above the burner. The flame plate spreads the flame out and the flames heat the side walls of the bell. The heat from the flames is conducted back down to the base of the burner which is where the vaporization of the fuel is going on.

What the caps do is capture the vapor stream and emit it through hundreds of tiny holes. There are then hundreds of teeny flames that bathe the rim of the bell in heat and the heat is conducted back to the base of the burner to vaporize the fuel. Lots of teeny flames are much quieter than one big monster flame.

You can see how the flame plate sits on the bells of these two Primus 96 stoves.

This is a burner from a Phoebus 625 which really shows the bell structure well.

It is pretty straightforward to replace a flame plate with a silent cap on a bell-shaped burner. Just pop the flame plate off and add the cap to replace it. Here’s a MSR FireFly stove shown with a flame plate and then a silent cap.

But, so far, nobody has been able to come up with a way to remove the flame ring on a standard roarer burner with that overhead vaporization chamber and add some sort of device to make it silent.

Believe me when I say I have thought long and hard on how to make a “cap” for the traditional overhead vapo chamber roarer. I’ve tried a few experiments, too. Nothing that’ll work so far. The feller who can come up with a way to silence these burners is going to have a really popular product on their hands. 😉

The good news is that Optimus made a silent version of your 111 stove in two different flavors, the 111T and the 111C. These came standard with a third type of burner which is designed to operate very quietly straight from the factory, no aftermarket caps needed.

111T:

111C (out of it’s case ‘cause I was working on it):

The 111T is much more common, but both stoves show up on eBay from time to time.

I hope this helps explain things. Good luck to you if you decide to pursue a 111T or C on eBay. They are really nice stoves – you wouldn’t go wrong if you bought one.